苄胺在超临界水中脱氮机理的量子化学计算

Quantum Chemistry Calculation on the Mechanism of Benzylamine Denitrogenation in Supercritical Water

针对苄胺在超临界水中的脱氮机理,通过实验和量子化学计算相结合的方法进行了研究。使用Gaussian09计算软件在M06/6-311G(d,p)和M06-2X/6-311+G(d,p)计算水平上进行量子化学计算。结果表明,苄胺在超临界水中的脱氮过程遵循协同反应机理而不是自由基机理。两步脱氢反应是苄胺的主要脱氢反应,其能垒(181.4 kJ·mol^(-1))比一步脱氢反应低118.7 kJ·mol^(-1)。由脱氢反应得到的苯甲醛进一步与苄胺反应生成亚苄基苯胺(BBA),BBA与超临界水继续反应实现脱氮过程。此外,通过比较有水催化和无水催化的反应能垒,发现超临界水分子对苄胺脱氮过程具有显著的催化作用。

The denitrogenation mechanism of benzylamine in supercritical water was studied by experiment and quantum chemistry calculation. The quantum chemistry calculation was performed by Gaussian09 software package at M06/6-311 G( d,p) and M06-2X/6-311+G( d,p) levels. Results show that the denitrogenation process of benzylamine is conform to concerted reaction mechanism instead of the free radical one.Two-step dehydrogenation,which is first presented,is the main dehydrogenation reaction of benzylamine.The energy barrier of this two-step dehydrogenation reaction is 181. 4 kJ·mol^(-1),which is 118. 7 kJ·mol^(-1) lower than that of traditional one step dehydrogenation reaction. Benzaldehyde derived from the dehydrogenation reaction was reacted with benzylamine,and generating benzylidenebenzylamine( BBA). The degradation process was continued through the reaction of BBA with supercritical water. Besides,the supercritical water molecules have a significant catalytic effect on the denitrogenation process of benzylamine,as shown by comparing the energy barrier of the reactions with and without water catalyst.